During the last decades, soil degradation has increased due to deforestation, agricultural activities, industrial activities, vegetation overexploitation and excessive grazing. To avoid and potentially reverse soil degradation, many different types of soil enhancers have been developed and are already being used today. Among the most common soil enhancers are fertilizers. Fertilizers improve the supply of nutrients in the soil, directly affecting plant growth. However, despite the wide spread use of fertilizers, conventional fertilizers are inefficient, particularly in soils with low cation exchange capacities and humid climate conditions. The demand for frequent application, susceptibility to being washed out/leaching, and the need for nutrients to be constantly replenished are a few of the many problems associated with conventional fertilizers. Therefore, controlled released fertilizers (CRF) have become the preferred type of fertilizers to improve nutrient yield while minimizing losses. CRF's have the ability to supply nutrients gradually to soil and plants over a longer period of time. By coinciding with the nutrient requirements of the plant, CRF's ensure improved effectiveness through minimizing the losses between application and absorption, thus avoiding losses by leaching, runoff, and nutrient volatilization.
A second known type of soil enhancer consists of microbes, such as beneficial fungi or plant growth promoting bacteria (“PGPB”). PGPB are rhizosphere-associated organisms that colonize the rhizosphere and rhizoplane and improve plant growth when artificially inoculated into soil. PGPB can both promote plant growth and fight pathogenic fungi. Current methods for deploying microbes into the environment often lead to the microbes being compromised and even dying before they can be fully incorporated into the environment. Thus a system or method to deploy them which will better maintain their viability and effectiveness is needed for the industry to fully realize the benefits of microbial use.
A third known type of soil enhancer is biochar. Biochar has been known for many years as a soil enhancer. It contains highly porous, high carbon content material similar to the type of very dark, fertile anthropogenic soil found in the Amazon Basin known as Terra Preta, which has very high carbon content and historically has been made from a mixture of charcoal, bone, and manure. Biochar is created by the pyrolysis of biomass, which generally involves heating and/or burning of organic matter, in a reduced oxygen environment, at a predetermined rate. Such heating and/or burning is stopped when the matter reaches a charcoal like stage. The highly porous material of biochar is suited to host beneficial microbes, retain nutrients, hold water, and act as a delivery system for a range of beneficial compounds and additives suited to specific applications.
Raw biochar, while known for its soil enhancing characteristics, does not always benefit soil and, depending upon the biomass from which the biochar is produced and the method of production, can potentially be harmful to the soil, making it unsuitable for various types of crops or other productive uses. In particular, biochar can be detrimental, or even toxic, to 1) soil microbes involved in nutrient transport to the plant; 2) plants and 3) humans. Biochars derived from different biomass or produced with differing parameters, such as higher or lower pyrolysis temperature or variations in residence time, will have different physical and chemical properties and can behave quite differently when used in agriculture. For example, biochar having pH levels too high, containing too much ash, inorganics, or containing toxins or heavy metal content too high can be harmful and/or have minimal benefit to the soil and the plant life it supports. Biochar can also contain unacceptable levels of residual organic compounds such as acids, esters, ethers, ketones, alcohols, sugars, phenyls, alkanes, alkenes, phenols, polychlorinated biphenyls or poly or mono aromatic hydrocarbons which are either toxic or not beneficial to plant or animal life.
Due to the unpredictable performance of biochar and its potential to be detrimental to plant life and growth, it has mostly been a scientific curiosity, not found wide spread use, not found large scale commercial application, and has been relegated to small niche applications. It is, however, known, as noted above, that biochar, having certain characteristics can host beneficial microbes, retain nutrients, hold water, and act as a delivery system for a range of beneficial compounds suited to specific applications. Thus, it has been a continued desire to capture the beneficial soil enhancing characteristics of biochar in a more consistent, predictable way. Biochar research has continued in an attempt to harness biochar having predictable, controllable, and beneficial results as a soil amendment for large scale applications.
Additionally, attempts have been made to narrowly combine the benefits of fertilizer with biochar by mixing it with, coating it with or submersing it in the fertilizer. The results of these attempts, however, have failed to adequately allow soil nutrient exposure and plant nutrient uptake to occur over a longer period of time throughout a growing season from the same application.
There are currently around 7 billion people in the world and this is expected to increase to approximately 8 billion around the year 2020. In light of both the expected worldwide population increase and the increasing environmental damage caused by ever greater levels of industrialization, it will become more and more of a challenge to feed all of the world's people, a problem that will only increase with time. Thus, a need exists, in order to feed this growing population, for a method of combining the benefits of fertilizer, beneficial fungi, PGPB or other additives with biochar in a manner that reduces the cost and impact of the frequent application of nutrients to the soil and increases agricultural productivity in a sustainable and environmentally friendly manner.